A comprehensive spectroscopic study of Mn2+ doped PbS nanocrystals

Abstract

Zero-dimensional Mn2+ doped PbS semiconductor nanocrystals with Mn2+ concentration varying between 0.05 and 0.52% (wt%) have been synthesized by simple chemical routes. This work is an effort to dope one of the most studied semiconductor PbS nanocrystal system with one of the widely studied transition metal dopant Mn2+ ion and describes new physical properties that have emerged following successful synthesis of these nanocrystals. The PbS:Mn nanocrystals have cubic structure (space group Fm3m), the average crystallite size lies between 5 and 10 nm and lattice constant $$a$$ slightly changes with the variation of doping concentration of Mn2+ ions as characterized by X-ray diffraction (XRD). The structural properties of PbS:Mn nanoparticles are also studied by high resolution transmission electron microscopy (HRTEM) analysis and UV/Vis absorption spectrum. The quantitative chemical analysis of pure and Mn2+ doped PbS nanocrystals have been done with the help of energy dispersive spectroscopy (EDS) spectra. The energy band gap have been determined by UV/Vis absorption study with the help of Tauc plot and are 1.50, 1.54, 1.57 and 1.65 eV for 0, 0.05, 0.26 and 0.52% Mn2+ doped PbS nanocrystals, respectively. The crystallite size also obtained from the UV/Vis absorption study varies between 5.53 and 5.20 nm with the increase of Mn2+ concentration from 0.05 to 0.52% which are in good agreement with XRD and HRTEM results. The luminescence behaviour of the nanocrystals has been studied by photoluminescence (PL) spectra. The magnetic and electronic properties of PbS:Mn nanocrystals are studied using electron paramagnetic resonance (EPR) spectra and the values of the electron $$g$$ factor, the second-rank axial zero-field splitting parameter D and the hyperfine parameter A are calculated.